The ruble and Russian shares fell on Monday as the oil price tumbled to a five-year low and the Central Bank appeared to refrain from interventions in the currency market. At 8:27 p.m. Moscow time, the ruble was down 2.4 percent against the dollar at 53.66 and down 2.3 percent against the euro at 65.80. The ruble-based MICEX share index was down 3.13 percent at 1,481 points and the dollar-based RTS was down 4.22 percent at 870 points, having earlier set a five-year low of 872. The price for Brent crude was down almost 3 percent at 67.15, having earlier dipped below $67 per barrel for the first time since September 2009. Oil and gas account for around 70 percent of Russia's exports.On Friday, the ruble had closed up 3 percent against the dollar. That was linked to Central Bank interventions to support the currency, traders said, but there was little sign of more interventions so far on Monday.

Russia resumed gas flows to Ukraine on Tuesday after halting them six months ago in a dispute over prices and unpaid debts, Ukraine's gas transport monopoly said.

"Ukraine has started receiving Russian gas. The volume of imports is around 43.5 million cubic meters per day," Ukrtransgaz spokesman Maxim Belyavsky said. Supplies will flow via the northern Belarussian pipeline of Mozyr and the eastern Sudzha route, he added. The ex-Soviet republic consumes about 200 million cubic meters on average per day during the winter. Without Russian gas and short of coal because separatist violence has disrupted domestic coal mining, Ukraine has been forced to introduce widespread power cuts. With relations poor because of the fighting in Ukraine's east, Russia had insisted that Ukraine pay upfront for renewed supplies over the winter, under an interim agreement in October.

The chief editor of an independent news portal in Siberia was assaulted on Monday night by two young men posing as delivery couriers, just hours after the agency's website was targeted by a DDoS attack, coworkers said. The head of Taiga.Info, Yevgeny Mezdrikov, was hospitalized with a broken nose after two attackers gained their way into the news agency's office in the center of Novosibirsk and gave him several blows to the face. Mezdrikov was released later that night after doctors dismissed a preliminary diagnosis of a possible concussion following an X-ray scan, Taiga.Info journalist Yaroslav Vlasov, told independent Dozh television. Vlasov, who witnessed the incident and tried to interfere, said the attackers entered the office posing as couriers carrying boxes, walked up to the chief editor and asked whether he was, indeed, Yevgeny Mezdrikov, to which the chief editor assented.